Air Handling Unit Refurbishment 

Five Star Hotel. Mayfair, London.

Our client said, “We are an award-winning, 5-star hotel with a deep commitment to holistic wellness of all staff and our guests. We want to separate ourselves from venues that are not heated, air-conditioned, or ventilated well, as this will make guests' stay unpleasant, especially at our large crowd events. We want our guests to know we are superior to others.”


This London, Mayfair based hotel operates 24/7/365, therefore we had to deliver this project with zero disruption. 


All works had to be completed over only 2 evenings and scheduled to allow for ventilation to continue during daytime hours.


The AHU required a deep clean, new coil installations, pipe work modifications, rust treatments, new filtration systems, fan upgrades, damper remediations, new anti-leakage seals, with full commissioning, and BMS integrations. 


Fan Upgrade & AHU Remodelling

Prior to installation Halo HVAC validated all technical aspects of the system, designed structural modifications of the AHU, pre-wired all fans, along with Internal-rotor motor PM/EC technology that boasts an efficiency of IE6,  exceeding motor energy efficiency classes set by both the International Electrotechnical Commission and European Efficiency. 


The new maintenance-free fans were installed into the Air Handling Unit, for both supply and extract air streams. Along with bespoke manufactured reinforced bulk heads and fan openings for a seamless installation.


This combines three solutions in a way that previously seemed almost impossible: Reliability, outstanding system efficiency with high-power density for environmental control and 15–20-year extended life cycle for each AHU. 



HALO HVAC AHU refurb - air handling unit refurbishment

High Efficiency Filtration System 

HALO HVAC AHU refurb - air handling unit refurbishment

Although we have been known to utilise IAQ technologies such as UVGI, and ionisation treatment, to improve indoor air quality (IAQ). Considering the nature of this five-star hotels function, the likelihood of potential side-effects and down time is much lower with a suitably designed and maintained high-efficiency filtration system.


The system we developed and installed has ease and simplicity of maintenance at the forefront. We installed a new high-quality air filtration system designed to effectively capture and remove airborne contaminants. To ensure the hotels deep commitment to holistic wellness of all staff and guests, the new filtration system is compliant to ISO 16890-1:2016, EN 779:2012, DIN 53438-3 (F1) and OEKO-TEX® 100. 


With Halo HVAC IOT it is possible to continuously remote monitor IAQ and accurately adjust based on live data to guarantee a consistent maintenance schedule.



HALO HVAC AHU refurb - air handling unit refurbishment
HALO HVAC AHU refurb - air handling unit refurbishment

Heating & Cooling coil upgrade 

HALO HVAC AHU refurb - air handling unit refurbishment

Prior to the upgrade, our technical survey engineer identified microbial contamination, rust, a coil capacity Issue, off coil temperature issues, blockages and a failed condensate drip tray and drain.


We designed a new coil process that involved the calculation of peak heating & cooling loads, specification of system and equipment configuration, calculation of annual performance, whilst taking into perspective noise, humidity and IAQ.


Our engineers supplied and installed replacement coils. To do this, the AHU cover panels were removed, as necessary. Unsecured the existing coils and removed them from the air handling units. The area vacated by the redundant coils was then thoroughly cleaned with anti-microbial cleaner that produces zero VOCs, and rust treatment was applied where applicable. 


The new coils were positioned into the air handling units and secured as required. New pipework connections installed. All panels were refitted with new anti-leakage seals, all redundant coil materials were removed from the site in line with ISO14001.


Lower Noise

When we begin the strategic design of a new fan system, our engineers design it so that the fan speed, and the vibration caused by the rotational speed, does not cause the system to operate in a region of resonance, we achieve this  through the calculation of the systems overall psychoacoustics.


With this project being a five-star hotel, peace and quiet is one certainty the guests want to experience. The result with our installation achieved a reduction of 11 dB(A) LpA. This was enabled thanks to upgrading the fans to a new system that uses no belts or pulleys with better air flow conditions, new reinforced fan bulk heads for less vibration, new anti-leak seals, new efficient heating & cooling coils and the use of noise reducing baffle and separation plates. 



AHU (asset) life extension

Issues arising from AHUs ageing present key challenges for building services. Technological advances and ever-changing compliance requirements, means that there are many air handling units operating beyond their originally conceived application. As HVAC equipment ages, increased challenges to maintaining integrity require to be managed – coinciding with potential declining financial value. This may be a result of cumulative degradation over time such as neglect, corrosion, rust, microbial growth, and environmental conditions such as serving a greater occupancy than when the AHU was first designed, and therefore the AHU doesn't achieve the airflow and thermal conditions required. Where like for like replacements is no longer suitable due to either obsolescence or changes in engineering standards Halo HVAC will have a solution. 




HALO HVAC AHU refurb - air handling unit refurbishment

Over time, this air handling unit suffered with degradation, largely due to a lack of maintenance and required fan, coil and filter remediation, a full service, a deep clean, including VOC free rust treatment, new doors, air leakage seals throughout, and damper repairs to meet compliance. 


Additionally, upgrading an AHU prevents unforeseen downtime, improved maintenance, compliance, efficiency, and added value to the asset in its entirety. Halo HVAC conducts asset audits, covering planned preventative maintenance, monitoring, risk management, and financial evaluation including return on investments.

Project Delivery ☆☆☆☆☆

Hotels operate 24/7 therefore we had to deliver this project with minimal disruption. We completed all works in 2 evenings and staged the works to allow for ventilation to continue during daytime hours.  The system deep clean, new coil installations, pipe work modifications and rust treatments were conducted and commissioned on the first evening.  The new filtration systems, fan upgrades, damper remediation, new anti-leakage seals and commissioning, and BMS integrations were carried out the following evening. 





HALO HVAC AHU refurb - air handling unit refurbishment

To enable an efficient “hassle-free” project delivery, and apart from the coils that were custom built within the unit, most components were pre-designed and fabricated off site. Ensuring safety, compliance, and risk mitigation to support an impeccable project delivery. This process enabled us to maximise on site time and guarantee the health and safety of everyone throughout the entirety of this project. 





Energy Saving Report

We conduct energy saving reports for all our delivered projects. No matter how small the saving may seem, a saving is a saving. 

Typically, we deliver a 40% saving on every delivered project. 





HALO HVAC AHU refurb - air handling unit refurbishment
HALO HVAC AHU refurb - air handling unit refurbishment

Conformity & Compliance

HALO HVAC Ltd has passed industry leading conformity and compliance testing, verification, and inspection. Our accreditations highlight our technical competences, reliability, and integrity to provide confidence and trust to deliver our services.


We hold insurances for Contractors All Risk, Professional Indemnity, Employer Liability, Public and Product Liability, and Contract Works. We are members of Constructionline, Building Engineering Services Association, and The Contractors Health and Safety Schemes in Procurement including PAS91 and SSIP.


Call to request copies on 0207 117 2087 or email


Clean Room & Labs, Chandlers Ford 

13 Air Handling Units serving a critical manufacturing process and science laboratories, all requiring refurbishments, controls and BMS modifications, delivered in 5 days, whilst achieving 26t a year CO2e reduction.


5 Star Hotel, Knightsbridge, London

The belt-driven fans in the hotel's air handling units failed, causing no ventilation in critical areas; urgent reinstatement was essential for to ensure the Hotel was fully operational & compliant.


Kettering General Hospital

Bringing the Air Handling Unit in line with compliances such as HTM 03-01 whilst reclaiming lost heat through new ventilation strategies, enabling energy savings.


Food Manufacturer, Rugby

Ventilation is vital for food production, ensuring air quality and contamination prevention. Upgraded filtration and AHU refurbishment guaranteed compliance, reliability and effectiveness.


Offices. Gracechurch Street, London 

With the building owners advertising for new leases a key objective was to ensure the indoor environment is comfortable and healthy. Over time, the existing AHUs became less efficient, leading to higher energy bills and reduced indoor air quality.


5 Star Hotel. Mayfair, London

This luxury hotel operates 24/7 therefore we had to deliver this project with zero disruption. We completed all works in 2 evenings whilst staging the works to allow for ventilation to continue during daytime hours. 


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